if you turn carbon dioxide into jet fuel, will anyone buy it?

Chemists think they figured out the process of capturing the greenhouse gas to turn it into fuel for airplanes. But the big question is whether we’d actually want to do this.
airplanes at airport terminal
Photo illustration by Ashim D’Silva

Here’s an unusual recipe for you. Carefully combine iron, manganese, and potassium. Set the result aside. Take citric acid, hydrogen, and carbon dioxide, add the catalytic mixture you’ve just created, and bring the whole thing to 350 °C until all components combine. Allow the vapor to condense into a liquid. Congratulations, you just made jet fuel in a process not too dissimilar from a concept originally intended for space exploration, and found a solution to recycling the carbon dioxide generated by flight. Well, not you exactly, that’s the achievement of a team of chemists from Oxford University who think their idea could help factories, foundries, and airports get a lot more environmentally friendly.

Since a lot of industrial processes emit carbon dioxide, it makes sense to try and capture as much of it as possible, but simply trying to sequester it is a liability and makes running all those industrial processes more expensive. Being able to turn it into fuel that someone would want to buy could add a major incentive for factories to clean up their acts at a profit, which is why the team is trying to find industrial partners to invest in portable jet fuel reactors, drive down high initial costs, and start selling the end product to airlines until they can switch to more efficient and eco-friendly modes of propulsion. Even better, carbon could be drawn out of the air as well, countering the effects of eventually burning this new jet fuel.

But unfortunately, this idea may not add up to much. First and foremost, air travel accounts for maybe 2.5% of all anthropogenic carbon pollution. Secondly, the reactors to make this carbon dioxide-based fuel will be expensive at the onset, so will the fuel while existing fuel is priced to move. Thirdly, there are alternative fuels which will in theory pollute far less and are made from biomass or leftover cooking oils, meaning that it would be cost competitive with existing jet fuel. Fourth, there are other major pollutants emitted from jet engines left unaddressed by this idea. And finally, to deal with aircraft emissions while boosting our own mental health, we can always just plant more trees and invest in green spaces.

With all that in mind, imagine trying to engage a major foundry to spend $20 million or more to figure out how to capture and isolate all their carbon dioxide emissions, buy and boil the other chemical agents to create a jet fuel they may not be able to sell, and then have to sequester the rest of the greenhouse gases they produce to help drive down one gas from a sector that barely registers as a contributor to global warming. Best case scenario, they may agree to a study. A more realistic outcome is executives in suits politely listening, nodding, promising to get back to you, then either not returning your phone calls or sending a polite email wishing you luck in your future endeavors.

In other words, this seems like an instance of a good idea being far too convoluted to work as millions of factories around the world will have to be persuaded to invest millions of dollars each into making a questionably marketable product instead of just using this money to get greener in the first place. Tax incentives from governments trying to encourage green energy and jobs may be far more beneficial to these factories’ bottom line, and hoping to raise billions to solve 2.5% of a problem instead of replacing their usually carbon-heavy power sources — which contribute an order of magnitude more to global warming than air travel — with green-friendly ones isn’t a very wise use of capital.

See: Yao, B., et al, (2020) Transforming carbon dioxide into jet fuel using an organic combustion-synthesized Fe-Mn-K catalyst, Nature Communications 11, 6395, DOI: 10.1038/s41467-020-20214-z

# science // chemistry / environment / global warming

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